Shantha Kumar T
Themes in SharePoint Server 2010 have been redesigned to simplify the process of generating themes. Themes created in Microsoft Office SharePoint Server 2007 are not compatible with SharePoint Server 2010. If you are upgrading from Office SharePoint Server 2007 to SharePoint Server 2010, you can use Visual Upgrade to continue to use sites in the old user interface. However, Microsoft recommend that you use the new user interface in SharePoint Server 2010 to create themes and apply them to your sites.